Anisian (Middle Triassic) bivalves from the Dolomites (Italy)

The Anisian (Middle Triassic) was an important phase in the evolution of marine biota, because reef-building metazoans re-appeared after the end-Permian mass extinction, and other taxa, such as bivalves, began their Mesozoic adaptive radiation. Anisian bivalves from the Dont Formation (Braies/Prags Group) of the Dolomites (Italy) are here figured and described for the first time. Most of the individuals were found in the fossil-lagerstatte of Monte Pra della Vacca/Kuhwiesenkopf, a deposit containing a transported assemblage composed of abundant and well diversified terrestrial plants and marine nektonic and benthonic taxa, which accumulated in a basinal environment. Further bivalves were collected in other parts of the formation, which is more than 200 m thick in this section. Thirteen bivalve species are classified here. The most common, long ranging species are Mysidioptera cainalloi (STOPPANI), Neomorphotis compta (GOLDFUSs), Entolium discites (SCHLOTUEIM), Newaagia noetlingi (FRECH), Pleuromya c musculoides (SCHLOTHEIM), P. brevis (ASSMANN) and Neoschizodus? sp. Others, such as Plagiostoma striatum (SCHLOTHEIM) and Pseudoplacunopsis fzssistriata (WINCKLER), have been found only in the plant bearing deposit, or in a fossiliferous horizon located in the upper part of the formation [Parallelodon esinensis (STOPPANI), Pteria? sp., Entolium kellneri (KITTL), and Chlamys (Praechlamys) cf. schroeteri (ASSMANN)].